This invention relates to a method of immobilizing circuitry fingers and bonding the circuitry to an IC chip. In particular, it relates to forming a coating of a liquid adhesive on the surface of a release film in a pattern of strips, rendering the coating non-tacky, bonding the strips of coating on the release film across the fingers of circuitry, removing the release film from the coating, and bonding an integrated circuit (IC) chip to the coating.
In manufacturing microelectronic components, silicon wafers are made that contain large numbers of IC chips. The wafers are cut and the individual chips are bonded to lead frames which enable wires to be attached to the chips. Alternatively, a cluster of chips can be bonded to a matching cluster of lead frames. After epoxy molding, the assembly is cut into individual packages of chips and lead frames.
The lead frames are stamped out of thin metal and consist of a multiplicity of delicate fingers attached to supports. The fingers are eventually cut, but during the cutting or mounting of the chips and other devices to the lead frames, the fingers can be bent at various angles or otherwise damaged, resulting in a poor bond.